Method for the producion of refractory containers



Nov. 27, 1962 D. F. EDNELL 3,066,069

METHOD FOR THE PRODUCTION OF REFRACTORY CONTAINERS Filed May 1, 1959wash/roe. DAN/EL FREDR/K EDNELL ATTORNEX United States Patent 3,066,069METHOD FOR THE PRODUCTION OF REFRACTORY CONTAINERS Daniel FredrikEdnell, Ed, Sweden Filed May 1, 1959, Ser. No. 810,479 Claims priority,application Norway May 23, 1958 1 Claim. (Cl. 162-227) This invention isconcerned with the forming of refractory containers, such as thoseemployed as moulds for the casting of metals, and is particularlyconcerned with the method of forming such containers from refractoryfibres suspended in liquid, from which suspension the fibres are appliedto a model form of mould forming a coating thereon, which coating isthereafter processed to the final container product.

In order to provide a sutficiently cohering coating upon the modelmould, the refractory fibres must be mixed with a binder substance. Thisis particularly necessary if the suspension, besides containing thefibres, contains a finely ground refractory material in order that thefinal product will consist of a mixture of fibres and such finely groundmaterial.

Prior efforts to form the desired refractory containers were directedtoward proceeding in the known manner employed in the production ofother forms of containers such as those consisting, for instance, ofcellulose fibres. There a suspension of the fibres in a liquid isformed, a perforate model mould is supported in the suspension, and alayer of fibres is formed upon the model mould by means of suction fromwithin the mould. This prior procedure did not, however, enablesatisfactory results to be achieved; satisfactory containers having thedesired wall thickness and adequately large dimensions were notobtainable.

After numerous experiments, however, it was discovered and this is thebasis for the instant invention, that the problem could be solved in asimple manner, for instance by applying the fibres to the model mould bymeans of pressure instead of by means of suction.

Thus the object of this invention consists in a method for manufacturingrefractory containers, especially moulds for casting of metals, which ischaracterised by the steps of suspending a mixture of refractory fibres,and possibly finely ground fireproof material, and a binder agent in aliquid, then dipping a perforate model mould into the suspension, whichlatter is subjected to air pressure, so that material from the suspendedmixture is pressed onto the model mould until a layer of desiredthickness has been deposited thereon, whereafter the model mould withits coating is removed from the suspension, and the coating is furtherprocessed'to a final container.

The invention also includes an apparatus for effecting said method. Themost characteristic features of said apparatus will appear from theshowing in the annexed drawing furnishing by way of example anembodiment of such an apparatus.

FIGURE 1 shows an elevation, partially in section, of the main portionof the apparatus, and

FIGURE 2 illustrates the use of the model mould in connection with acombined removing and drying cup for the formed container.

The illustrated apparatus for use in carrying out the method of theinvention comprises a vessel 1, which consists of an upper member 1a anda lower member 1b, which members may be combined or removed from eachother by means of a suitable device, such as an eccentric not shown.Tightening of the members together is obtained by means of a gasket 2.The upper member 1a may be raised for a certain distance, for instance25 mm., above the lower member 112 and thereafter be shifted laterally3,066,069 Patented Nov. 27, 1962 ice,

for positioning over a combined removing and drying cup 11, which isdescribed in more detail below. In the combined condition of the members1a and 1b the vessel shall be able to withstand an inner air pressure of5-10 kgs. Air under pressure may be supplied to the upper part of thevessel through the tube 3.

Within the vessel 1 a model mould 5 is suspended by means of an upwardlyand downwardly movable rod 4. The rod 4 passes through a pressure tightpacking (not shown) at the top of the container. Said model mould has aliquid penetrable portion, consisting of a wire screen placed upon aperforate plate, the latter being carried by an interned steel skeleton.The lower box-formed portion 5a of the mould and the lid portion thereofconsist of solid metal. In the lid are provided openings for tubes 6 and7.

The combined removing and drying cup 11 seen in FIG. 2 is open at itsbottom and top. Below the cup 11 a box 12 is positioned and providedwith a packing, by means of which the open bottom portion of the cup maybe completely closed by causing the box 12 to be raised by means of aneccentric so that the box makes a close fit with the cup.

The method of operation is as follows:

Through tubes 9 the container 1 is filled with a suspension 8 ofrefractory fibres, admixed with binding agent, up to the level shown inFIGURE 1. If desired the suspension may contain also finely groundrefractory material. The model mould 5 is lowered into the suspension 8by means of the rod 4, and compressed air is applied to the interior ofthe container 1 through the tube 3. The suspension is thereby pressedagainst the model mould a d suspended material is deposited upon theperforate portion thereof, whereas liquid flows through said portioninto the interior of the model mould. The model mould remains stationaryuntil a layer 10 of desired thickness has been formed thereupon. Themodel mould 5 is then raised by means of the rod 4 to above the level ofthe liquid in the container, and the air pressure Within the containerthen drives the water, which had accumulated within the model mould 5,out through the tube 7. When the water has been driven out of the modelmould, the admission of compressed air is cut off, and the top vesselmember 1a is lifted so that the mould 5 is a little above the lowervessel member 1b. Thereafter the member 1a together with model mould 5and coating thereon is shifted horizontally by suitable means, notshown, until the model mould arn'ves over the removing cup 11, situatednear by the vessel. By means of the rod 4 the model 5 with coatingthereon is then lowered into the removing cup 11, whereby the outer faceof the coating is smoothened. 'Ihen compressed air is admitted throughthe conduit 6, whereby the fibre container loosens from the model mould,which latter is then raised bymeans of the rod 4, and together with thecontainer member 1a shifted back to starting position.

The cup 11 with the already shaped container therein is passed into adrying chamber or the like, After drying the container is taken out ofthe combined removing and drying cup and may, if desired, be heated toincandescence before being put to use. In this manner large containersmay be manufactured Without difiiculty for instance such containershaving a diameter greater than /2 m., which are hard and very durable,and which are by way of example suitable for use when casting metals,such as steel.

I claim:

The method of producing refractory containers, particularly molds forthe casting of metals which comprises, introducing a mixture ofrefractory fiber and a binder agent into a liquid occupying the lowerportion of a closed chamber and suspending said mixture in said liquid,immersing a hollow perforated mold Within such suspension, subjectingsuch suspension to air pressure to deposit said suspended mixture ontothe outer surface of said mold to form a layer thereon and when a layerof desired thickness has been applied raising said mold above the levelof said liquid while maintaining the same Within said closed chamber andforcing liquid out of said layer by maintaining said air pressure withinthe portion of said chamber above said liquid.

References Cited in the file of this patent UNITED STATES PATENTS KassonAug. 14,

Hawley June 12,

Abrahams et al. Dec. 23,

Binkley Jan. 11,

FOREIGN PATENTS Great Britain July 13,

Germany Aug. 31,

